Conventional methods for segmentation of tissue images are prone to misclassification of objects in tissue (e.g., epithelial and stromal nuclei) and may produce irregular nuclei, incorrectly identify cytoplasm boundaries, and result in over and under-segmentation of clustered nuclei. These problems are exacerbated by variations in image acquisition conditions and image artifacts.
Existing systems for characterizing objects (e.g., glands) in tissue images are also predicated upon the need for accurate and repeatable segmentation of lumens in the image. However, segmentation of lumens can be difficult as cancer progresses. Specifically, tissue architecture may typically consist of isolated or touching gland rings surrounded by fibromuscular tissue (stroma). Each gland ring may include rows of epithelial cells surrounding a duct (lumen). The connected glandular cytoplasm (e.g., epithelial unit) may include a gland ring. However, as cancer progresses, epithelial cells replicate in an uncontrolled way, disrupting regular ring structures. For example, in Gleason grade 4, epithelial units fuse together creating chains of gland rings, or dense cribriform sheets of rings, all in the same epithelial unit, while lumens shrink or disappear. In existing segmentation systems, this can lead to touching/fused epithelial cells/units. Existing segmentation systems also have difficulty performing segmentation based on lumens, which have shrunk or disappeared. The same segmentation difficulty arises for Gleason grade 5, where the tumor loses these structures and becomes undifferentiated sheets of epithelial cells and/or epithelial fragments.
More accurate, reliable, and repeatable systems and methods for processing, segmentation, and feature extraction from images (e.g., tissue images) are needed, for example, to allow for the generation of improved predictive models for diagnosing, treating, and/or predicting the occurrence of medical conditions. These and other objects of the present invention are satisfied according to various embodiments of the present invention described herein.